Shell Programming and Scripting

You might want to know what you did wrong to arrive at something different as expected:

Matches in "sed" are always "greedy". That means of different possible matches always the longest possible is taken. That means:

Code:

$ cat input
xxx [abc] yyy [def] zzz

$ sed -n 's/.*\[//;s/\].*//p' input
def

because /.*\[/ has two possibilities to match something: xxx [ and xxx [abc] yyy [. Of these two options it will always take the second one, never the first one. The second rule s/\].*//p will therefore only get def] zzz" to see, from which it cuts ] zzz.

Seasoned crafters of regexps write therefore, instead of ".*[", "[^[]*[". This is a "negated character class", meaning anything other than a "[", followed by a "[". This expression will always be matched by the nearest anchor character.

I hope this helps.

bakunin

Thank you guys. Thanks for all the suggestions. I was able to resolve my issue.